Battery residual quantity display method and electronic equipment

ABSTRACT

The present invention is directed to a battery residual quantity display method for performing display of battery residual quantity of a battery pack mounted at an electronic equipment and serving to supply power to the electronic equipment. When power is turned ON, a first microcomputer ( 3 ) of the camera body ( 1 ) side serves to first acquire, by serial communication, information for battery residual quantity display from a second microcomputer ( 7 ) of the battery pack ( 2 ) side loaded at the camera body to perform battery residual quantity display on the basis of the acquired information to subsequently acquire, by serial communication, information for authentication processing from the second microcomputer of the battery pack side to perform an authentication processing for judging on the basis of the acquired information as to whether or not the battery pack connected to the camera body is genuine battery pack to update, after the authentication processing, the content of the battery residual quantity display on the basis of information for battery residual quantity display acquired by serial communication from the microcomputer of the battery pack side.

TECHNICAL FIELD

The present invention relates to a battery residual quantity displaymethod in an electronic equipment comprising an equipment body withinwhich a microcomputer having communication function is mounted, and abattery pack detachably loaded at the equipment body and adapted so thata microcomputer having communication function to perform serialcommunication to and from the microcomputer of the equipment body sideis mounted, the battery pack serving to supply power to the equipmentbody, and an electronic equipment using such a display method.

This application claims priority of Japanese Patent Application No.2005-067818, filed on Mar. 10, 2005, the entirety of which isincorporated by reference herein.

BACKGROUND ART

Hitherto, there are used electronic equipments, e.g., image pick-upapparatuses such as video camera and/or digital still camera, mobiletelephone, and/or personal computer, etc. using, as power supply,battery pack where a secondary battery such as lithium ion battery, NiCdbattery or nickel-hydrogen battery, etc. is included.

In the battery pack used in electronic equipments of this kind, thereare included therewithin, e.g., a microcomputer for performing residualquantity calculation of the battery, and/or communication to and fromthe electronic equipment using such battery pack as a power supply,peripheral circuits of the microcomputer, and a circuit for detectingthe state of battery cell, which is necessary for performing residualquantity calculation of battery, etc. As a battery pack of this kind,there is a battery pack described in the Japanese Patent ApplicationLaid Open No. 1997-297166 publication.

Moreover, portable or mobile information processing apparatuses such asPDA (Personal Digital Assistant), etc. have network connecting function,whereby there is performed user authentication processing to confirmthat concerned user is authorized user in order to comply withelectronic settlement using such network connecting function withenhancement of processing ability. For example, there is performed,e.g., a method of performing communication of information relating toauthentication between charging unit and control means within the mobileinformation processing apparatus to protect personal information andsecret information, which are stored within the mobile informationprocessing apparatus, on the basis of result of the authenticationconfirmation. As an equipment having a function of this kind, there isan equipment described in the Japanese Patent Application Laid Open No.2004-310387 publication.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention

Meanwhile, in electronic equipments using, as a power supply, batterypack within which secondary battery is included, there are many caseswhere battery packs dedicated therefor are used every equipment. Whenbattery pack dedicated for corresponding equipment is not used, thereresults a cause to lead breakage/damage, etc. of the equipment body.

Moreover, hitherto, in the case of performing communication ofinformation between charging unit and control means within mobileinformation processing apparatus to perform authentication of battery,authentication processing of battery is performed prior to otherprocessing so that when battery authentication processing is notcompleted, it is impossible to perform other processing.

Further, even in the case of the same battery, authentication of thebattery is performed every time before other processing is performedafter power is turned ON.

Hitherto, since authentication processing of batteries used inelectronic equipments of the same kind are collectively performed, aperson who attempts to prepare non-genuine battery facilitates toanalyze a method of authentication of battery. Further, loads ofmicrocomputer of the set side (equipment body) and microcomputer of thebattery side are great, and microcomputer operative at a high speed isrequired so that cost is increased. Moreover, as stated above, loads ofmicrocomputers of the set side and the battery side are great. As aresult, it is necessary to operate the microcomputer at a high speed sothat power consumption is disadvantageously increased.

Moreover, in conventional battery packs, only either one of the batteryresidual quantity display function and the battery authenticationprocessing function is provided. In order to have both functions toperform, at the same time, battery residual quantity display and batteryauthentication processing, two independent communication systems of theset and the battery are required. As a result, communication lines oftwo systems are required so that cost of the hardware is increased. Inaddition, communication drivers of two systems are required so thatdevelopment cost of software is disadvantageously increased.

In view of the above, an object of the present invention is to provide abattery residual quantity display method and an electronic equipment,which are capable of providing both functions of battery residualquantity display and battery authentication processing withoutincreasing load of the microcomputer.

The present invention is directed to a battery residual quantity displaymethod in an electronic equipment comprising an equipment body withinwhich a microcomputer having communication function is mounted, and abattery pack detachably loaded at the equipment body and adapted so thata microcomputer having communication function to perform serialcommunication to and from the microcomputer of the equipment body sideis mounted, the battery pack serving to supply power to the equipmentbody. In this method, when power is turned ON, the microcomputer of theequipment body side serves to first acquire, by serial communication,information for battery residual quantity display from the microcomputerof the battery pack side loaded at the equipment body to perform batteryresidual quantity display on the basis of the acquired information.Then, the microcomputer of the equipment body side serves to acquire, byserial communication, information for authentication processing from themicrocomputer of the battery pack side loaded at the equipment body toperform authentication processing to judge on the basis of the acquiredinformation as to whether or not the battery pack connected to theequipment body is genuine battery pack. The microcomputer of theequipment body side serves to update, after the authenticationprocessing, the content of battery residual quantity display on thebasis of information for battery residual quantity display, which isacquired, by serial communication, from the microcomputer of the batterypack side.

Moreover, the present invention is constituted as an electronicequipment comprising an equipment body within which a microcomputerhaving communication function is mounted, and a battery pack detachablyloaded at the equipment body and adapted so that a microcomputer havingcommunication function to perform serial communication to and from themicrocomputer of the equipment body side is mounted, the battery packserving to supply power to the equipment body. When power is turned ON,the electronic equipment to which the present invention is appliedserves to first acquire, by serial communication, information forbattery residual quantity display from the microcomputer of the batterypack side loaded at the equipment body to perform battery residualquantity display on the basis of the acquired information. Then, themicrocomputer of the equipment body side serves to acquire, by serialcommunication, information for authentication processing from themicrocomputer of the battery pack side loaded at the equipment body toperform authentication to judge on the basis of the acquired informationas to whether or not the battery pack connected to the equipment body isgenuine battery pack, and the microcomputer of the equipment body sideserves to update, after the authentication processing, the content ofbattery residual quantity display on the basis of information forbattery residual quantity display, which is acquired, by serialcommunication, from the microcomputer of the battery pack side.

In the present invention, authentication of the battery is performed tothereby make it impossible to use coarse battery at the set (equipmentbody), thus making it possible to prevent, in advance, breakage/damage,etc. of equipment body by use of the battery except for normal orgenuine battery.

Moreover, in the present invention, since only battery residual quantitydisplay is performed without performing authentication processing of thebattery until the remaining usable time can be displayed for a firsttime, there is no possibility that the function of the residual quantitydisplay of the battery which is merit for user may be damaged by batteryauthentication processing.

Further, in the present invention, battery residual quantity displayprocessing and battery authentication processing are performed withinthe same system so that there is no necessity of independently havingsignal lines between the set and the battery. As a result, reduction ofthe cost of the hardware can be realized. Further, since it issufficient to provide communication driver of one system, developmentcost of the software can be reduced.

Furthermore, in the present invention, the battery authenticationprocessing is divided to perform battery authentication processing inthe middle of the residual quantity display processing of the battery sothat not only it becomes difficult that a bad-will person such as maker,etc., who prepares coarse battery analyzes a way of performingauthentication, but also battery authentication can be performed even ifhigh performance microcomputer is not used. For this reason, the cost isreduced. Further, since battery authentication can be performed even ifthe microcomputer is not used at a high speed, the power consumption canbe reduced.

In addition, in the present invention, since battery authenticationresult is stored, user can concentrate on battery residual quantitydisplay processing at the second time operation when power is turned ONand operations subsequent thereto. Thus, direct merit with respect touser can be protected.

Still further objects of the present invention and practical meritsobtained by the present invention will become more apparent from theembodiments which will be explained below with reference to the attacheddrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing an embodiment of a video camera towhich the present invention is applied.

FIG. 2 is a view showing the state transition of software used in thevideo camera.

FIG. 3 is a flowchart showing processing executed at microcomputer ofthe camera body side and microcomputer of the battery pack side whichconstitute the video camera.

FIG. 4 is a time chart showing how state shifts with respect to elapsedtime in the processing by the method of the present invention and theconventional method.

BEST MODE FOR CARRYING OUT THE INVENTION

The embodiments of the present invention will now be described in detailwith reference to the attached drawings. It should be noted that thepresent invention is not limited to the embodiments shown below, but itis a matter of course that changes or modifications may be made asoccasion demands within the scope of the knowledge that personsordinarily skilled in the art have within the scope which does notdepart from the gist of the present invention.

The present invention is applied to, e.g., a video camera 100 having aconfiguration as shown in FIG. 1. The video camera 100 is composed of acamera body 1, and a battery pack 2 detachably loaded at the camera body1 and serving to supply power through connection terminals.

At the camera body 1, there are provided a first microcomputer 3, a LCD(Liquid Crystal Display) 4, a non-volatile memory 5, and several otherdevices 6 necessary for constituting the video camera 100.

The first microcomputer 3 is connected to the LCD 4, the non-volatilememory 5 and other devices 6, and serves to control those components.

Here, while there are lens driver of the image pick-up optical system,imager driver of the image pick-up unit and driver of therecording/reproduction system as other devices 6 necessary for the videocamera 100, since those devices are not directly required forexplanation of the present invention, detailed explanation thereof willbe omitted in the following explanation.

Within the battery box of the camera body 1, there are provided aconnection terminal 67 connected to the first microcomputer 3, and apower supply input terminal 68 of the plus side and a power inputterminal 69 of the minus side of the camera body 1.

The first microcomputer 3 provided at the camera body 1 can performserial communication to and from the external via the connectionterminal 67.

The battery pack 2 comprises a battery cell 8 such as lithium ionbattery, etc., a current detection resistor 9 having one end connectedto the cathode (positive electrode) of the battery cell 8, a secondmicrocomputer 7 having both ends connected to the current detectionresistor 9, and a non-volatile memory 66 connected to the microcomputer7.

At the battery pack 2, there are provided a connection terminal 10connected to the second microcomputer 7, a power supply input terminal11 of the plus side connected to the cathode of the battery cell 8through the current detection resistor 9, and a power supply inputterminal 12 of the minus side connected to the anode (negativeelectrode) of the battery cell 8.

The second microcomputer 7 provided at the battery pack 2 can performserial communication to and from the external via the connectionterminal 10.

Further, when the battery pack 2 is inserted into the battery box of thecamera body 1, connection terminals 10, 11, 12 of the battery pack 2side are respectively connected to the connection terminals 67, 68, 69of the camera body 1 side. As the result of the fact that the connectionterminals 11, 12 of the battery pack 2 side are respectively connectedto the connection terminals 68, 69 of the camera body 1 side, power isdelivered from the battery pack 2 to the camera body 1. Moreover, as theresult of the fact that the connection terminal 10 of the battery pack 2side is connected to the connection terminal 67 of the camera body 1side, serial communication can be performed between the firstmicrocomputer 3 of the camera body 1 side and the second microcomputer 7of the battery pack 2 side.

The battery residual quantity display at the video camera 100 isperformed in a manner as described below.

Namely, the second microcomputer 7 of the battery pack 2 side serves tomeasure potential difference across both terminals of the currentdetection resistor 9 to calculate, at a predetermined period, a currentwhich has flowed into the battery cell 8 and a current which has flowedfrom the battery cell 8 to integrate current quantities to calculatebattery current quantity usable or available at present to grasp thecalculated current quantity thus obtained.

Further, the first microcomputer 3 of the camera body 1 side stores, inadvance, current consumption value Is of the camera body 1 into thenon-volatile memory 5 to acquire current quantity Ia of the battery pack2 usable at present by serial communication from the battery sidemicrocomputer 7 to calculate remaining usable time Ta of the batterypack 2 by the following formula (I).Ta=Ia/Is  (1)to display the calculated remaining usable time Ta on the liquid crystaldisplay 4.

Further, battery authentication at the video camera 100 is performed ina manner as described below.

Namely, the first microcomputer 3 of the camera body 1 side and thesecond microcomputer 7 of the battery pack 2 side have common certaininformation. The common information is stored into the non-volatilememory 5 at the camera body 1 side, and is stored into the non-volatilememory 66 at the battery pack 2 side.

Further, the microcomputer 7 of the battery pack 2 side reads out commoninformation from the non-volatile memory 66 to transmit the commoninformation thus obtained to the first microcomputer 3 of the camerabody 1 side.

The first microcomputer 3 of the camera body 1 side receives commoninformation, by serial communication, from the second microcomputer 7 ofthe battery pack 2 side to read out the common information which hasbeen stored in the non-volatile memory 5 of the camera body 1 side toperform comparison with information which has been obtained from thebattery pack 2 side, whereby when both information coincide with eachother, it is judged that inserted battery is genuine battery pack 2which can be properly used. The first microcomputer 3 of the camera body1 side records, into the non-volatile memory 5, information indicatingthat battery authentication has been completed and informationindicating that inserted battery is genuine battery.

Moreover, when both information do not coincide with each other, thefirst microcomputer 3 of the camera body side 1 is imitated ornon-genuine battery. When it is judged that the inserted battery isnon-genuine battery, information indicating “Since the battery insertedat present is non-genuine battery, please use genuine battery” isdisplayed on the liquid crystal display 4, and information indicatingthat authentication of the battery has been completed and informationindicating that the inserted battery pack 2 is not genuine battery arerecorded into the non-volatile memory 5. After a predetermined time ispassed, power of the camera body 1 is turned OFF.

In the video camera 100, common serial communication lines 13, 14 areused for communication between the first microcomputer 3 of the camerabody 1 side and the second computer 7 of the battery pack 2 side.

Further, in the battery residual quantity display processing and thebattery authentication processing, data described below is caused toundergo transmission/reception between the first microcomputer 3 of thecamera body 1 side and the second microcomputer 7 of the battery pack 2side.

Namely, in the battery residual quantity display processing,transmission/reception of integrated value of current quantities whichhave been flowed through the current detection resistor 9 and pluralbattery residual quantity correction values are performed.

It is to be noted that, in the battery residual quantity processing, inprinciple, it is sufficient that the first microcomputer 3 of the camerabody 1 side receives only usable current quantity of the battery fromthe second microcomputer 7 of the battery pack 2 side.

In practice, usable current quantity of the battery pack 2 is notdetermined only by integrated value of current quantities by the currentdetection resistor 9. This is because usable current quantity of thebattery pack 2 is changed by elements such as voltage at which thecamera body 1 is operable, current voltage and/or degree of agingdeterioration of the battery pack 2, etc.

In the explanation of the present invention, these elements are called“battery residual quantity correction value”.

As “battery residual quantity correction coefficient”, there is batteryresidual quantity correction coefficient in which it is sufficient thattransmission/reception is performed only once after communication isstarted, and there is battery residual quantity correction coefficientin which transmission/reception must be repeatedly performed at apredetermined period. The former communication is called “batteryresidual quantity display initial communication”, and the lattercommunication is called “battery residual quantity display ordinarycommunication”.

In this embodiment, transmission/reception operations of fourteen numberof data are performed as ‘battery residual quantity display initialcommunication’, and transmission/reception operations of eighteen numberof data are performed as ‘battery residual quantity display ordinarycommunication’.

In the battery authentication processing, transmission/receptionoperations of plural “information that the camera body 1 side and thebattery pack 2 side commonly have” are performed.

If communication of only one “information that the camera body 1 sideand the battery pack 2 side commonly have” is performed, “batteryauthentication” can be made. However, if a person who attempts toprepare non-genuine battery analyzes a method of “batteryauthentication” to find out one common information, it would be possibleto prepare imitated, i.e., non-genuine battery. In view of the above, inthe present invention, communicating operations of eight number ofcommunication information is performed to confirm that all commoninformation coincide with each other at the camera body 1 side and thebattery 2 side to thereby perform “battery authentication”.

It is to be noted that the number of “information that the camera body 1side and the battery pack 2 side commonly have” is not limited to eight,but may be any number of information.

Moreover, when communication of “information that the camera body 1 sideand the battery pack 2 side commonly have” is performed, communicationof values after undergone any operation may be performed withoutperforming communication as it is.

Here, software executed at the first microcomputer 3 of the camera body1 side and the second microcomputer 7 of the battery pack 2 side in thevideo camera 100 will be explained.

The software of this embodiment has following five states, and performsstate transition as shown in FIG. 2.

The state ST1 is battery residual quantity display initial communicationstate. The microcomputer 3 of the camera body 1 side and themicrocomputer 7 of the battery pack 2 side perform communication ofbattery residual quantity correction value in which acquisition is madeonly once among “battery residual correction values” necessary forresidual quantity calculation of the battery. Between the firstmicrocomputer 3 of the camera body 1 side and the second microcomputer 7of the battery pack 2 side, fourteen times of communications areperformed.

Moreover, the state ST2 is battery residual quantity display ordinarycommunication state. The first microcomputer 3 of the camera body 1 sideand the second microcomputer 7 of the battery pack 2 side performcommunication of “battery residual quantity correction value” and“integrated value of current quantities by the current detectionresistor 9” in which acquisition is periodically necessary among datanecessary for residual quantity display of the battery pack 2. Betweenthe first microcomputer 3 of the camera body 1 side and the secondmicrocomputer 7 of the battery pack 2 side, eighteen times ofcommunications are performed.

Further, the state ST3 is battery residual quantity calculation state.The first microcomputer 3 of the camera body 1 side calculates remainingusable time of the battery pack 2 on the basis of “battery residualquantity correction value” and “integrated value of current quantitiesby the current detection resistor 9” which have been acquired in thebattery residual quantity display initial communication state ST1 andthe battery residual quantity ordinary communication state ST2 todisplay the calculated remaining usable time thus obtained on the liquidcrystal display 4.

Further, the state ST4 is the battery authentication communicationstate. The first microcomputer 3 of the camera body 1 side and thesecond microcomputer 7 of the battery pack 2 side perform communicationof “information that the first microcomputer 3 of the camera body 1 sideand the second microcomputer 7 of the battery pack 2 side commonlyhave”. Between the first microcomputer 3 of the camera body 1 side andthe second microcomputer 7 of the battery pack 2 side, eight number ofcommunications in total are performed.

In addition, the state ST5 is OFF state, wherein notification of “Sincebattery inserted at present is non-genuine battery, please use genuinebattery” is displayed on the liquid crystal display 4. The firstmicrocomputer 3 of the camera body 1 side records, into the non-volatilememory 5, ‘Information indicating “Battery authentication” has beencompleted’ and ‘Information indicating that inserted battery is notgenuine battery’. After a predetermined time is passed, power source ofthe camera body 1 is turned OFF.

Then, the state transition immediately after reset of the system will beexplained in order.

Namely, when the first microcomputer 3 of the camera body 1 side and thesecond microcomputer 7 of the battery pack 2 side are reset, shift fromall states to the battery residual quantity display initialcommunication state ST1 is performed to perform communication of batteryresidual quantity correction value in which acquisition is necessaryonly once among “battery residual quantity correction values” necessaryfor residual quantity calculation of the battery. Thus, fourteen timesof communications are performed between the first microcomputer 3 of thecamera body 1 side and the microcomputer 7 of the battery pack 2 side.

Further, when processing of the battery residual quantity displayinitial communication state ST1 is entirely completed, communicationstate of the first microcomputer 3 of the camera body 1 side and thesecond microcomputer 7 of the battery pack 2 side shifts to the batteryresidual quantity display ordinary communication state ST2. Thus, thefirst microcomputer 3 of the camera body 1 side and the secondmicrocomputer 7 of the battery pack 2 side perform communication of‘battery residual quantity correction value’ and ‘integrated value ofcurrent quantities by the current detection resistor 9’ in whichacquisition is periodically required among data necessary for residualquantity display of the battery pack 2. Thus, eighteen times ofcommunications are performed between the first microcomputer 3 of thecamera body 1 side and the second microcomputer 7 of the battery pack 2side.

Then, when processing of the battery residual quantity display ordinarycommunication state ST2 is entirely completed, communication state ofthe first microcomputer 3 of the camera body 1 side and the secondmicrocomputer 7 of the battery pack 2 side shifts to the batteryresidual quantity calculation state ST3. Thus, the first microcomputer 3of the camera body 1 side calculates remaining usable time of thebattery pack 2 on the basis of “battery residual quantity correctionvalue” and “integrated value of current quantities by the currentdetection resistor 9” which have been acquired in the battery residualquantity display initial communication state ST1 and the batteryresidual quantity display ordinary communication state ST2 to displaythe calculated remaining usable time thus obtained on the liquid crystaldisplay 4.

Then, when processing of the battery residual quantity calculation stateST3 is entirely completed, communication state of the firstmicrocomputer 3 of the camera body 1 side and the second microcomputer 7of the battery pack 2 side shifts to the battery residual quantitydisplay ordinary communication state ST2 to perform communication of“battery residual quantity correction value” or “integrated value ofcurrent quantities by the current detection resistor 9” in whichacquisition is periodically necessary among data necessary for residualquantity display of the battery pack 2. Only one communication isperformed between the first microcomputer 3 of the camera body 1 sideand the microcomputer 7 of the battery pack 2 side.

Then, when only one communication is completed between the firstmicrocomputer 3 of the camera body 1 side and the second microcomputer 7of the battery pack 2 side in the battery residual quantity displayordinary communication state ST2, communication state of the firstmicrocomputer 3 of the camera body 1 side and the second microcomputer 7of the battery pack 2 side shifts to the battery authenticationcommunication state ST4 to perform communication of ‘information thatthe first microcomputer 3 of the camera body 1 side and the secondmicrocomputer 7 of the battery pack 2 side commonly have’. Thus, onlyone communication is performed between the first microcomputer 3 of thecamera body 1 side and the second microcomputer 7 of the battery pack 2side.

Then, when only one communication is completed between the firstmicrocomputer 3 of the camera body 1 side and the second microcomputer 7of the battery pack 2 side in the battery authentication communicationstate ST4, communication state of the first microcomputer 3 of thecamera body 1 side and the second microcomputer 7 of the battery 2 sideshifts to the battery residual quantity display ordinary communicationstate ST2 to perform communication of ‘battery residual quantitycorrection value’ or ‘integrated value of current quantities by thecurrent detection resistor 9’ in which acquisition is periodicallynecessary among data necessary for residual quantity display of thebattery pack 2. Thus, only one communication is performed between thefirst microcomputer 3 of the camera body 1 side and the secondmicrocomputer 7 of the battery pack 2 side.

Further, the first microcomputer 3 of the camera body 1 side and thesecond microcomputer 7 of the battery pack 2 side repeat the statetransition from the battery residual quantity display ordinarycommunication state ST2 to the battery authentication communicationstate ST4 and the state transition from the battery authenticationcommunication state ST4 to the battery residual quantity displayordinary communication state ST2 until eight number of communications intotal of “information that the first microcomputer 3 of the camera body1 side and the second microcomputer 7 of the battery pack 2 sidecommonly have” are completed in the battery authentication communicationstate ST4.

Then, when eight number of communications in total of “information thatthe first microcomputer 3 of the camera body 1 side and the secondmicrocomputer 7 of the battery pack 2 side commonly have” are completedin the battery authentication communication state ST2, the firstmicrocomputer 3 of the camera body 1 side and the second microcomputer 7of the battery pack 2 side read out common information stored in thenon-volatile memory 5 of the camera body 1 side to perform comparisonwith information obtained from the second microcomputer 7 of the batterypack 2 side.

Then, when both information coincide with each other, the firstmicrocomputer 3 of the camera body 1 side judges that inserted batteryis genuine battery. On the contrary, when both information do notcoincide with each other, the first microcomputer 3 of the camera body 1side judges that inserted battery is non-genuine battery.

Further, in the case where it is judged that inserted battery is genuinebattery, the first microcomputer 3 of the camera body 1 side records,into the non-volatile memory 5, ‘information indicating that “batteryauthentication” has been completed’ and ‘information indicating thatinserted battery is genuine battery’. Thereafter, communication stateshifts to the battery residual quantity display ordinary communicationstate ST2. At times subsequent thereto, the first microcomputer 3 of thecamera body 1 side and the second microcomputer 7 of the battery pack 2side perform only communication of ‘battery residual quantity correctionvalue’ or ‘integrated value of current quantities by the currentdetection resistor 9’. In the case where there is no change in value of‘battery residual quantity correction value’ or ‘integrated value ofcurrent quantities by the current detection resistor 9’, thecommunication state remains in the battery residual quantity displayordinary communication state ST2. In the case where there takes placechange in value of ‘battery residual quantity correction value’ or‘integrated value of current quantities by the current detectionresistor 9’, the communication state shifts to the battery residualquantity calculation state ST3 to calculate, for a second time,remaining usable time of the battery pack 2 to update display of theliquid crystal display 4.

Further, in the case where it is judged that inserted battery isnon-genuine battery, the communication state of the first microcomputer3 of the camera side 1 shifts to the OFF state ST5 to display, on theliquid crystal display 4, notification of ‘Since battery inserted atpresent is non-genuine battery, please use genuine battery’, and torecord, into the non-volatile memory 5, ‘information indicating that“battery authentication” has been completed’ and ‘information indicatingthat inserted battery is not genuine battery’ to turn power source ofthe camera body 1 OFF after a predetermined time is passed.

Then, the processing executed at the first microcomputer 3 of the camerabody 1 side and the second microcomputer 7 of the battery pack 2 side inthe video camera 100 will be explained with reference to the flowchartshown in FIG. 3.

Namely, in the video camera 100, when power of the camera body 1 isturned ON, the first microcomputer 3 of the camera body 1 side and thesecond microcomputer 7 of the battery pack 2 side are first placed inthe battery residual quantity display initial communication state ST1 toperform fourteen number of communications of ‘battery residual quantitycorrection value’ (steps SA1˜SA14, steps SB1˜SB14).

Then, the first microcomputer 3 of the camera body 1 side and the secondmicrocomputer 7 of the battery pack 2 side are placed in batteryresidual quantity display ordinary communication state ST2 to performeighteen number of communications of ‘battery residual quantitycorrection value’ (steps SA15˜SA32, steps SB15˜SB32).

Then, the first microcomputer 3 of the camera body 1 side calculatesremaining usable time of the battery pack 2 on the basis of acquired(14+18)=32 number of ‘battery residual quantity correction values’ (stepSA33).

Then, the first microcomputer 3 of the camera body 1 side displaysremaining usable time of the battery pack 2 on the liquid crystaldisplay 4 (step SA 34).

Then, the first microcomputer 3 of the camera body 1 side and the secondmicrocomputer 7 of the battery pack 2 side are placed in the batteryresidual quantity display ordinary communication state ST1 to performonly one ‘battery residual quantity correction value’ (steps SA35,SB33).

Then, the first microcomputer 3 of the camera body 1 side and the secondmicrocomputer 7 of the battery pack 2 side are placed in the batteryauthentication communication state ST4 to perform communication of onlyone ‘information that the set side and the battery side commonly have’(steps SA36, SB34).

Further, the first microcomputer 3 of the camera body 1 side and thesecond microcomputer 7 of the battery pack 2 side repeat (stepsSA35˜SA36, steps SB33˜SB34) until communications of eight number of‘information that the set side and the battery side commonly have’ intotal are completed in the battery authentication communication stateST4.

Then, the first microcomputer 3 of the camera body 1 side reads outcommon information stored in the non-volatile memory 5 of the camerabody 1 side to compare the common information thus read out withinformation obtained from the second microcomputer 7 of the battery pack2 side (step SA37).

Further, when the both information coincide with each other, the firstmicrocomputer 3 of the camera body 1 side judges that inserted batteryis genuine battery to record, into the non-volatile memory 5,‘information indicating that “battery authentication” has beencompleted’, and ‘information indicating that inserted battery is genuinebattery’ (step SA38). Thereafter, there results ‘battery residualquantity display ordinary communication state (ST2) to perform onlycommunication of ‘battery residual quantity correction value’.

Moreover, when the both information do not coincide with each other, thefirst microcomputer 3 of the camera body 1 side judges that insertedbattery is non-genuine battery thereafter to display, on the liquidcrystal display 4, notification of ‘Since battery inserted at present isnon-genuine battery, please use genuine battery’, and to record, intothe non-volatile memory 5, ‘information indicating that “batteryauthentication” has been completed’ and ‘information indicating thatinserted battery is not genuine battery’ to turn power source of thecamera body 1 OFF after a predetermined time is passed (step SA39).

In the video camera 100, processing shown in the flowchart of FIG. 3 isexecuted by the first microcomputer 3 of the camera body 1 side and thesecond microcomputer 7 of the battery pack 2 side. Thus, when power ofthe equipment body 1 is turned ON as indicated by the timing chart shownat (A) in FIG. 4, there first results battery residual quantity displayordinary communication state ST2 via the battery residual quantitydisplay initial communication state ST1. Thus, remaining usable time ofthe battery is first displayed on the liquid crystal display 4.Thereafter, transition between the battery authentication communicationstate ST4 and the battery residual quantity display ordinarycommunication state ST2 is alternately performed. When theauthentication processing is completed, the battery residual quantitydisplay ordinary communication state ST2 repeats so that the content ofthe battery residual quantity display is updated.

Here, in the conventional battery authentication method of firstperforming battery authentication as indicated by the timing chart shownat (B) in FIG. 4, as compared to the conventional case of performingonly battery residual quantity display as indicated by the timing chartshown at (C) in FIG. 4, time at which remaining usable time of thebattery is first displayed is delayed by the time of the batteryauthentication communication state ST4. On the contrary, in this videocamera 100, since battery residual quantity display is first performedthereafter to perform authentication processing, there is no delay intime at which remaining usable time of the battery is first displayed ascompared to the case of performing only battery residual quantitydisplay.

Namely, in the video camera 100 to which the present invention isapplied, since only battery residual quantity display processing isperformed at first to perform battery authentication processing afterremaining usable time is displayed on the liquid crystal display 4, thetime required when remaining usable time is displayed at first is notchanged even if battery authentication processing is supplemented. Thus,there is no possibility that the function of the battery residualquantity display which is advantageous to user may be injured by thebattery authentication processing.

As stated above, in the video camera 100 to which the present inventionis applied, even when battery authentication is performed, the time atwhich remaining usable time of the battery, which is directlyadvantageous to user, is displayed at first is not sacrificed.

Moreover, in the video camera 100, since battery authentication isperformed in parallel to battery residual quantity display, it becomesimpossible to use coarse battery which is not genuine battery. Thus, itis possible to prevent, in advance, breakage/damage, etc. of theequipment body 1 by use of battery pack except for genuine battery.

Further, in the video camera 100, since both the battery residualquantity display and the battery authentication are performed with theprocessing being subject to time-division by using the communicationsystem of the first microcomputer 3 of the camera body 1 side and thesecond microcomputer 7 of the battery pack 2 side, it is sufficient touse communication line of one system. Thus, the cost of the hardware canbe reduced.

Furthermore, in the video camera 100, the battery residual quantitydisplay processing and the battery authentication processing areperformed within the same system so that it is sufficient thatcommunication driver of the system is employed. Thus, development costof software can be reduced.

Still further, in the video camera 100, the battery authentication isdivided to perform battery authentication processing in the middle ofthe battery residual quantity display processing. Thus, a bad-willperson such as maker which manufactures coarse batteries, etc. makes itdifficult to analyze a method of performing authentication.

Still more further, in the video camera 100, since the batteryauthentication processing is divided, it is possible to perform batteryauthentication even if high performance microcomputer is not used. Forthis reason, the cost can be reduced.

Further, in the video camera 100, since the battery authenticationprocessing is divided, it is possible to perform battery authenticationeven if microcomputer is not used at a high speed. For this reason,power consumption can be reduced.

Furthermore, in the video camera 100, since battery authenticationresult is stored, user can concentrate on the battery residual quantitydisplay processing from the second time when power is turned ON and timesubsequent thereto. Advantages to user can be protected.

In addition, since the video camera 100 can be used immediately afterbattery authentication, time at the time of battery exchange can beshortened particularly in such image pick-up apparatus, e.g., videocamera 100 and/or digital still camera. As a result, there is a littlepossibility that user may escape photographing chance. Thus, user canadvantageously continue photographing.

1. A battery residual quantity display method in an electronic equipmentincluding: an equipment body within which a microcomputer havingcommunication function is mounted; and a battery pack detachably loadedat the equipment body and adapted so that a microcomputer havingcommunication function to perform serial communication to and from themicrocomputer of the equipment body is mounted, the battery pack servingto supply power to the equipment body, the method comprising: acquiringby serial communication by the microcomputer of the equipment body sideinformation for battery residual quantity display from the microcomputerof the battery pack side loaded at the equipment body to perform batteryresidual quantity display on the basis of the acquired information whenthe power is turned on, the microcomputer acquiring the information forbattery residual quantity display even if authentication processing isbeing performed by the microcomputer; acquiring by the microcomputer ofthe equipment body side, by serial communication, information for theauthentication processing from the microcomputer of the battery packside loaded at the equipment body to perform authentication processingto judge on the basis of the acquired information as to whether or notthe battery pack connected to the equipment body is genuine batterypack; and updating by the microcomputer of the equipment body side,after the authentication processing, the content of battery residualquantity display on the basis of information for battery residualquantity display, which is acquired by serial communication from themicrocomputer of the battery pack side.
 2. The battery residual quantitydisplay method according to claim 1, wherein the microcomputer of thebattery pack side detects a current flowing out from the battery pack asinformation for the battery residual quantity display to integratecurrent quantities thereof to thereby grasp a current quantity of thebattery usable at present, and the microcomputer of the equipment bodyside serves to acquire, by serial communication, current quantity of thebattery usable at present as information for the battery residualquantity display from the microcomputer of the battery pack side loadedat the equipment body to calculate remaining usable time of the batteryon the basis of the acquired current quantity of the battery usable atpresent and current consumption value of the equipment to performbattery residual quantity display.
 3. The battery residual quantitydisplay method according to claim 1, wherein the microcomputer of theequipment body side and the microcomputer of the battery pack side havecommon certain information, and the microcomputer of the equipment bodyside receives the common information by serial communication from themicrocomputer of the battery pack side loaded at the equipment body tocompare the received information with information that the microcomputerof the equipment body side itself has to thereby perform anauthentication processing to judge the battery pack as to whether or notit is a genuine battery pack.
 4. The battery residual quantity displaymethod according to claim 1, wherein in the case where the microcomputerof the equipment body side judges that the battery pack loaded at theequipment body is not the genuine battery pack by the authenticationprocessing, it displays a notification thereof thereafter to cut offpower supply of the equipment body.
 5. The battery residual quantitydisplay method according to claim 1, wherein, in performing theauthentication processing, the microcomputer of the equipment body sidealternately receives information for the authentication processing andinformation for the battery residual quantity display from themicrocomputer of the battery pack side loaded at the equipment body toupdate, after the authentication processing, the content of batteryresidual quantity display on the basis of the information for batteryresidual quantity display which has been acquired by serialcommunication from the microcomputer of the battery pack side.
 6. Thebattery residual quantity display method according to claim 1, whereinthe microcomputer of the equipment body side stores, in advance, resultof the authentication processing to use the result of the authenticationprocessing in authentication processing at the second time when power isturned ON and times subsequent thereto.
 7. An electronic equipmentcomprising: an equipment body within which a microcomputer havingcommunication function is mounted; and a battery pack detachably loadedat the equipment body and adapted so that a microcomputer havingcommunication function to perform serial communication to and from themicrocomputer of the equipment body side is mounted, the battery packserving to supply power to the equipment body, wherein when power isturned ON, the microcomputer of the equipment body side is configured tofirst acquire, by serial communication, information for battery residualquantity display from the microcomputer of the battery pack side loadedat the equipment body to perform battery residual quantity display onthe basis of the acquired information, the microcomputer acquiring theinformation for battery residual quantity display even if authenticationprocessing is being performed by the microcomputer, the microcomputer ofthe equipment body side is configured to then acquire, by serialcommunication, information for the authentication processing from themicrocomputer of the battery pack side loaded at the equipment body tojudge on the basis of the acquired information as to whether or not thebattery pack connected to the equipment body is genuine battery pack,and the microcomputer of the equipment body side is configured toupdate, after the authentication processing, the content of batteryresidual quantity display on the basis of the information for batteryresidual quantity display, which is acquired, by serial communication,from the microcomputer of the battery pack side.
 8. The electronicequipment according to claim 7, wherein the information for batteryresidual quantity display indicates a usable amount of current remainingin the battery pack.
 9. The battery residual quantity display methodaccording to claim 1, wherein the information for battery residualquantity display indicates a usable amount of current remaining in thebattery pack.